import java.util.HashMap;

public class Test03 {
    public static void main(String[] args) {
        HashMap<String,Integer> hm=new HashMap<>();
        hm.put("aaa",1);
        hm.put("bbb",2);
        hm.put("ccc",3);
        hm.keySet().stream().forEach(s->System.out.println(s));
        hm.entrySet().stream().forEach(s->System.out.println(s));
    }
}
